Study Links Hepatitis B Exposure to Increased Pancreatic Cancer Risk

By Matthew Mahady

Published: Monday, May 24, 2010

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M.D. Anderson Cancer Center

In what researchers are touting as a first-of-its- kind finding, Houston-based University of Texas M. D. Anderson Cancer Center investigators have discovered a potential connection between exposure to the hepatitis B virus (HBV) and an increased risk of developing pancreatic cancer. The study, published in a recent issue of Journal of Clinical Oncology, suggests that the increased risk may go both ways: patients previously exposed to HBV who have pancreatic cancer and have undergone chemotherapy (the most common treatment for the disease) appear to have an increased chance of HBV recurrence.

The investigation began in 2000, and M. D. Anderson researchers have identified and tracked 476 patients with pancreatic cancer that was diagnosed at an early stage. Investigators created a control group that includes 879 people without pancreatic cancer. Control subjects were matched by age, gender, and race with subjects in the patient group. All participants were interviewed for demographic and risk-factor information. Researchers then tested the blood of all participants for the presence of hepatitis C (HCV) and HBV antibodies, which would indicate prior exposure to HCV and HBV.

HBV antibodies were significantly more prevalent in blood samples from people with pancreatic cancer than in the controls (7.6% vs 3.2%, respectively). The number of patients exposed to HCV, however, did not differ significantly between the 2 groups. In addition to these findings, the study also confirmed previously reported risk associations between cigarette smoking, history of diabetes, and a family history of pancreatic cancer with pancreatic cancer development.

People exposed to HBV may develop occult—or hidden—HBV infection. The M. D. Anderson researchers say that for these patients, chemotherapy may reactivate HBV. They speculate that chemotherapy suppresses the immune system, leading to viral replication of HBV. “If these results are validated, physicians might want to test pancreatic cancer patients for HBV before administering chemotherapy. Reactivation of HBV could potentially cause liver damage and even liver failure,” stated senior author James Abbruzzese, MD, professor and chair of M. D. Anderson's Department of Gastrointestinal Medical Oncology and associate medical director of the Gastrointestinal Center.

Researchers stress that these early results need to be studied further. They plan to collaborate with other institutions to compare results among other populations and people who are infected with HBV. If the results of this study are confirmed, they could offer new insight into pancreatic cancer development and treatment. It is possible that in the future, some cases of pancreatic cancer could be prevented.

“We are working hard to try to understand the factors that are risks to developing pancreatic cancer, particularly modifiable risks,” Dr. Abbruzzese said. “People at risk might be able to help prevent pancreatic cancer by getting an HBV vaccine.”

Lead author Manal Hassan, MD, PhD, assistant professor, Department of Gastrointestinal Medical Oncology, M. D. Anderson, concurred. “If this study is validated, it will give us more information about the risk factors of pancreatic cancer and possibly even help prevent it in some cases,” she said.

According to Dr. Hassan, although this study is the first to examine whether HBV exposure increases someone’s risk for pancreatic cancer, other research indicates that chronic HBV infection impairs pancreatic function and that HBV may replicate in the pancreas.

The word “hepatitis” means inflammation of the liver, and previous research has shown that HBV is a major cause of liver cancer. Not much is known about whether HBV plays a definitive role in other cancers. The proximity of the liver to the pancreas and the fact the pancreas and liver share common blood vessels and ducts make the pancreas a logical potential target for hepatitis viruses, however. Patients with pancreatic cancer often do not receive a diagnosis until the disease is advanced. The cancer is especially perplexing to clinicians, because there are few known pancreatic cancer risk factors at this time. The research M. D. Anderson has been doing in this area has the potential to expand on this knowledge considerably.